Xugang Zhang

Morphology, mechanical and thermodynamic properties of epoxy resins toughened with liquid acrylate oligomers containing carboxyl groups

Purpose – The purpose of this paper is to obtain liquid acrylate oligomers containing carboxyl groups as excellent toughening agents for epoxy resins.Design/methodology/approach – Liquid acrylate oligomers containing carboxyl groups were synthesised by the solution polymerisation of butyl acrylate (BA), acrylic acid (AA) and acrylonitrile (AN) as monomers. The liquid acrylate oligomers were used as the toughening agents for epoxy resins. The chemical structure of the oligomers was characterised by 13C nuclear magnetic resonance (NMR) spectroscope. The morphology of modified epoxy networks was analysed by scanning electron microscope (SEM). The mechanical and thermodynamic properties were measured by universal testing machine and dynamic mechanical analyser (DMA).Findings – The results show that AA and oligomer concentrations have great influence on the morphology, mechanical and thermodynamic properties of the modified epoxy networks. When the 10u2009wt percent oligomer containing BA and AN and AA in the rati...

Miscibility, morphology, mechanical, and thermodynamic properties of epoxy resins toughened with functionalized core-shell nanoparticles containing epoxy groups on the surface

Purpose – In order to obtain functionalized core-shell nanoparticles (CSNPs) as excellent toughening agents for epoxy resins. The paper aims to discuss these issues. Design/methodology/approach – Functionalized CSNPs containing epoxy groups on the surface were synthesized by emulsion polymerization with butyl acrylate as the core and methyl methacrylate copolymerizing with glycidyl methacrylate (GMA) as the shell. CSNPs were used as toughening agents for epoxy resins and their chemical structure was characterized by FT-IR. The morphology of modified epoxy networks (MEPN) was analyzed by SEM and TEM. Both the mechanical properties and thermodynamic properties were studied. Findings – The results show that nearly spherical CSNPs with the particle size of 50-100u2009nm are obtained. A certain amount of CSNPs are uniformly dispersed in epoxy resins by the grinding method and the MEPN shows the ductile fracture feature. The miscibility between CSNPs and epoxy matrix increases with the increase of GMA concentration...

Three-dimensional honeycomb-like porous carbon derived from corncob for the removal of heavy metals from water by capacitive deionization

In this study, porous carbon (3DHPC) with a 3D honeycomb-like structure was synthesized from waste biomass corncob via hydrothermal carbonization coupled with KOH activation and investigated as a capacitive deionization (CDI) electrode material. The obtained 3DHPC possesses a hierarchal macroporous and mesoporous structure, and a large accessible specific surface area (952 m2 g−1). Electrochemical tests showed that the 3DHPC electrode exhibited a specific capacitance of 452 F g−1 and good electric conductivity. Moreover, the feasibility of electrosorptive removal of chromium(VI) from an aqueous solution using the 3DHPC electrode was demonstrated. When 1.0 V was applied to a solution containing 30 mg L−1 chromium(VI), the 3DHPC electrode exhibited a higher removal efficiency of 91.58% compared with that in the open circuit condition. This enhanced adsorption results from the improved affinity between chromium(VI) and the electrode under electrochemical assistance involving a non-faradic process. Consequently, the 3DHPC electrode with typical double-layer capacitor behavior is demonstrated to be a favorable electrode material for capacitive deionization.

Epoxy composites with functionalized molybdenum disulfide nanoplatelet additives

As a typical layered inorganic analogue of graphene, molybdenum disulfide (MoS2) has gained intensive attention and become a research hotspot due to its unique two dimensional nanostructure and excellent properties. The enhancement in the thermal and mechanical properties of polymer/inorganic nanosheet composites depends strongly on their interfacial interaction. In this study, we exfoliated bulk MoS2 into nanosheets which were subsequently functionalized using 3-mercaptopropyltriethoxysilane. The functionalized MoS2 (f-MoS2) were dispersed in epoxy polymers at loading fractions of up to 1% by weight via ultrasonication and three roll mills. We characterized the tensile, fracture and adhesive properties of the composite and show that f-MoS2 nanoplatelets are highly effective at enhancing the mechanical properties of the epoxy at very low nanofiller loading fractions (0.1–0.7% by weight). Our results show the potential of functionalized 2D sheets of transition metal dichalcogenides as reinforcing additives in polymeric composites. The results indicate that the glass transition temperature increases significantly for the lower weight fraction composites, from 135 °C for the baseline (unfilled) epoxy to 146 °C at 0.7% f-MoS2 loading. The apparent shear strength at 120 °C increases significantly for the lower weight fraction composites, from 13.8 MPa for the baseline (unfilled) epoxy to 24.9 MPa at 0.7% f-MoS2 loading.